When an unsprung mass of a vehicle is reduced, there is an effect that riding comfortableness is improved, and fuel consumption can be reduced. As the most common means for reducing the unsprung mass as described above, a light-metal wheel is used as a wheel as disclosed in Japanese patent application Kokai publication No. 2002-274103.
In the case where the unsprung mass is reduced by use of the light-metal wheel, the larger a rate of the reduction gets, the more the riding comfortableness is improved. However, on the other hand, rigidity of the wheel is lowered. Thus, noise (road noise) generated in a vehicle interior tends to get gradually worse. Particularly, road noise of around 300 Hz frequency is increased. Therefore, an object in the case where the light-metal wheel is used is to figure out how the foregoing road noise of around 300 Hz frequency can be reduced.